<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
<button id="start">start</button>
<button id="stop">stop</button>
<div id="result"></div>
<script src="webworker.js"></script>
<script>
let startBtn = document.getElementById('start');
let stopBtn = document.getElementById('stop');
let result = document.getElementById('result');
startBtn.addEventListener('click', startWorker, false);
stopBtn.addEventListener('click', stopWorker, false);
let w ;
function startWorker() {
    if (typeof (Worker) !== "undefined") { // 浏览器嗅探 是否支持Worker功能
        if (typeof (w) == "undefined") { // 只能实例化一次 
            w = new Worker("webWorker.js");
        }
        w.onmessage = function(event){
            result.innerHTML = event.data;
        }
    } else {
        result.innerHTML = "Sorry, your browser 不支持"
    }
}

function stopWorker() {
    if(w){
        w.terminate();
    }
}

</script>
</body>
</html>